#include <iostream>
#include <cstring>
#include <cstdio>
#include <queue>
#define maxn 1010
using namespace std;char s[maxn][maxn];
int g[maxn][maxn];
int T,n,m;
int dx[4]={0,1,0,-1};
int dy[4]={1,0,-1,0};bool inside(int cx,int cy)
{return cx>0 && cx<=n && cy>0 && cy<=m;
}bool border(int cx,int cy)
{return cx==1 || cx==n || cy==1 || cy==m;
}void init_fire()
{for (int i=1; i<=n; i++)for (int j=1; j<=m; j++) g[i][j]=99999999;queue<int> qx,qy;for (int i=1; i<=n; i++)for (int j=1; j<=m; j++)if (s[i][j]=='F') qx.push(i),qy.push(j),g[i][j]=0;while (!qx.empty()){int cx=qx.front(),cy=qy.front();qx.pop(),qy.pop();for (int i=0; i<4; i++){if (!inside(cx+dx[i],cy+dy[i])) continue;if (s[cx+dx[i]][cy+dy[i]]!='.') continue;if (g[cx][cy]+1>=g[cx+dx[i]][cy+dy[i]]) continue;g[cx+dx[i]][cy+dy[i]]=g[cx][cy]+1;qx.push(cx+dx[i]),qy.push(cy+dy[i]);}}
}int bfs()
{queue<int> qx,qy;for (int i=1; i<=n; i++)for (int j=1; j<=m; j++)if (s[i][j]=='J'){g[i][j]=0;qx.push(i),qy.push(j);if (border(i,j)) return 1;}while (!qx.empty()){int cx=qx.front(),cy=qy.front();qx.pop(),qy.pop();for (int i=0; i<4; i++){if (s[cx+dx[i]][cy+dy[i]]!='.') continue;if (g[cx][cy]+1>=g[cx+dx[i]][cy+dy[i]]) continue;if (border(cx+dx[i],cy+dy[i])) return g[cx][cy]+2;g[cx+dx[i]][cy+dy[i]]=g[cx][cy]+1;qx.push(cx+dx[i]),qy.push(cy+dy[i]);}}return -1;
}int main()
{scanf("%d",&T);while (T--){scanf("%d%d",&n,&m);for (int i=1; i<=n; i++) scanf("%s",s[i]+1);init_fire();int ans=bfs();if (ans==-1) puts("IMPOSSIBLE");else printf("%d\n",ans);}return 0;
}